Lab-Grown Diamonds Sparkle Every Bit As BrightCommercial labs can now make the large, clear diamonds people prize for engagement rings and other jewelry in as little as 72 hours. How will this change the diamond industry?

Most diamonds are formed deep within the Earth, and sometimes the way they are mined can raise environmental and ethical concerns. The alternative, lab-grown diamonds, are finally emerging as a real competitor after nearly a half-century of research. Technology has advanced now to the point that it's possible for these labs to churn out huge, white diamonds - just the type you might want to wear. NPR's Nell Greenfieldboyce reports on how this is changing the diamond industry.

NELL GREENFIELDBOYCE, BYLINE: There's a company outside of Washington, D.C., called WD Lab Grown Diamonds. Yarden Tsach runs the place. He unwraps a little parcel of white tissue paper to show me a sparkly diamond.

GREENFIELDBOYCE: What they do is make diamonds. Tsach takes me into the lab. He doesn't let me get a close look at the machines, but I peek through a window. He says inside each machine is a vacuum chamber. At the bottom, they put a little bit of solid diamond. That's the seed for diamond growing. Then they add gases to the chamber and microwaves. This creates a reaction that deposits more and more carbon onto the seed, building the diamond up until it's big enough to look good on a ring.

TSACH: On most of the cases on the floor here it will think about eight weeks.

GREENFIELDBOYCE: And let's be clear - this isn't cubic zirconia or some fake.

TSACH: So it is diamond. It's not something else.

GREENFIELDBOYCE: But compared with diamonds mined from the ground, it can be more than 30 percent cheaper. That means people can buy a bigger diamond.

TSACH: The market is huge. We cannot satisfy the demand. We're expanding, and we still cannot satisfy the demand.

GREENFIELDBOYCE: This is just one of a bunch of diamond growing companies out there. Manmade diamonds are now appearing at tony retailers, like Barneys New York, which introduced them in October as a high-tech, eco-friendly alternative to mined gems. To see how all of this is going over it with the traditional diamond industry, I headed to New York City's famous diamond district. This one block of West 47th Street is crammed with shop windows filled with glittering diamonds. Right around the corner is the International Gemological Institute. It grades diamonds on the famous four Cs - cut, clarity, carats and color. David Weinstein is the executive director.

DAVID WEINSTEIN: I deal with diamond all day long for three decades. To me, diamonds aren't anything spectacular. You know, it's hard to get me to say wow.

GREENFIELDBOYCE: He pulls out some envelopes from a stack on his cluttered desk.

WEINSTEIN: And these are all laboratory-grown.

GREENFIELDBOYCE: He says in the old days, the rare lab-grown diamonds you'd see would be yellow or brownish - not any more.

WEINSTEIN: The quality has got to the point where they're astonishingly white.

GREENFIELDBOYCE: Lots of these diamonds come into his lab, and there's going to be a lot more. A recent report from the investment firm Morgan Stanley found that lab-grown diamonds currently make up maybe 1 percent of the global market, but it predicted that could grow to as much as 7 to 15 percent in the next few years. The Federal Trade Commission says gemstone marketers must be truthful about exactly what they're selling.

WEINSTEIN: I think there'll always be a distinction between what came out of the ground - what took millions and millions of years to make - and what was made in the last, you know, 72 hours.

GREENFIELDBOYCE: Weinstein can tell the difference between natural and lab-grown diamonds. For one thing, companies often laser-inscribe their manufactured diamonds, putting words like lab-grown right on them. But even if they didn't, Weinstein has microscopes and other instruments that can reveal a diamond's origin.

WEINSTEIN: We're not fooled. We feel a hundred percent confident that's something we can do, you know, all the time.

GREENFIELDBOYCE: The problem is while bigger diamonds generally get tested, a significant part of the diamond trade is very small stones. They're used to accent larger gems, or you might have a ring studded with teeny diamonds.

WEINSTEIN: For many manufacturers who make jewelry with small stones, it's just not economically feasible for them to send 10,000 stones into a laboratory and pay the expense to have every stone tested.

GREENFIELDBOYCE: Already there's been cases of undisclosed lab-grown diamonds getting mixed in with bulk batches of little diamonds. A few weeks ago, the U.S. jewelry Council hosted a meeting in New York for major players in the diamond business to discuss how to deal with this threat. One solution is new testing technologies. The Gemological Institute of America is a non-profit research institute. Its gleaming office building looms over the diamond district. Tom Moses is the chief research officer in this lab. He shows me a prototype of a machine that can test incredibly small diamonds in bulk. It looks like a glass box the size of a refrigerator with tubes and moving metal parts.

TOM MOSES: So you see all the little diamonds?

GREENFIELDBOYCE: No, I don't.

MOSES: Down there? You see them going in this white tray being loaded and picked up?

GREENFIELDBOYCE: Oh, those are diamonds.

MOSES: Yeah. There's thousands in there.

GREENFIELDBOYCE: They're the size of poppy seeds. Testing each one takes about two seconds and costs eight cents. The machine sorts the diamonds into either lab-grown or natural. Moses says his organization doesn't have any bias for one over the other.

MOSES: That's not our job to determine, you know, what's the right kind of diamond for an individual.

GREENFIELDBOYCE: But as lab-grown diamonds become more common, he thinks it's important that anyone buying a diamond is clear on whether it's mined or manufactured. Nell Greenfieldboyce, NPR News.

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